Machine for filleting fish



Feb. 25, 1936. H. s. Row'roN Err AL MACHIN FOR FILLETING FISH Filed Oct. 25, 1933 3 Sheets-Sheet 1 ggz@ NJN www Feb. 25, 1936.

H. S. ROWTON ET AL MACHINE FOR FILLETING FISH Filed Oct. 25, 1933 3 Sheets-Sheet 2 a I.. 3 n ra. a h f a 6 oo 4... 6 2M 2 on... 2 O.; l y. w z w 7 7 lmvv Naw 6 a 3 m.. \w s m w ,8 2 ||l l Il b D. :i a l..- L ma" l..- r AW MM ma M .a

Feb. 25, 1936. H. s. Row'roN 'ET AL MACHINE FOR FILLETING FISH 3 Sheets-Sheet 3 Filed OCT.. 25, 1933 estaras ses. 2s, was

UNITED STATES MACHINE For. rILLE'rmG FISH Harold Stanley Rowton and John Leslie Bowton,

. Aberdeen, Scotland Application October 25, 1933, Serial No. 695,092 In Great Britain October 29, 1932 31 Claims.

This invention has for its object to provide an improved apparatus for mechanically removing the flesh from the prismatic portion of the backbone of decapitated and eviscerated fish of the class having a backbone which comprises a prismatic spinal column terminating in a substantially fiat or oval-shaped spinal column, such as cod, haddock, hake, ling, pollock, bream and like salt water or fresh water fish.

A further object of the invention is to provide an improved apparatus which, while mechanically removing the flesh from the prismatic spinal column of such fish, will adapt itself to the natural curvature in the lengthwise direction of the backbone.

In the fllleting of such fish by hand labour it is usual to split the flesh on each side of the backbone to form two separate fillets of sh severed from one another at the backbone. In some cases, however, the backbone is removed without splitting the fish into two separate fillets, the latter process being known as block lleting. The present invention further has for its object to provide an improved machine for enabling either block filleting to be mechanically accomplished or to enable the fish to be mechanically split into two fillets.

According to the invention the improved apparatus for mechanically removing the flesh from the prismatic portion of the backbone of fish of the class stated comprises a double-bladed filleting tool stationarily mounted with respect to a conveyer adapted to convey the fish tail foremost (after it has been previously decapitated, eviscerated and slit along the oval portion of the backbone up to the navel or base of the prismatic spinal column) with the ventral or underside of the fish directed towards the filleting tool, the latter comprising a pair of blades spaced apart and having pointed forward extremities to enter the flesh of the fish at the two sides of the prismatic spinal column, and having elongated narrow portions in the rear of said forward extremities, said elongated portions gradually increasing in width towards the rear and each having a curved cutting edge which conforms to the curved anatomical lateral shape of the prismatic spinal column so as to cut through the flesh close to the sides of the prismatic spinal column which passes between the two blades.

The blades are preferably curved transversely from a point in rear of their pointed extremities to the rear of the blades, said transverse curvature conforming to the curved anatomical lateral shape of the prismatic spinal column.

Although it is preferred to mount the filleting tool in a stationary position with respect to a conveyer for carrying the fish past the tool, it will be understood that the fish could be held while travelling the tool past the fish. In either case it is essential however that the tool be so mounted that it does not move during the actual operation of the tool towards or away from the surface upon which the fish rests, although the tool may be adjustable towards or away from said surface when not in operation, for the purpose of adapting the tool to different sizes of sh.

Those edges of the blades which enter deeper into the fish may be shaped to cut through the back or dorsum of the fish on each side of the dorsal fins, leaving two fillets, or they may be so shaped that they do not penetrate the back or dorsum of the fish, in which case the central bone may be subsequently removed in such a manner that the flsh is produced as one fillet.

In order that the invention may be more clearly understood, reference is hereinafter made to the accompanying drawings illustrating one manner of carrying out the invention.

Fig. 1 is an elevational view of one side o1 the fish-dressing machine;

Fig. 2 is a plan view of the machine shown in Fig. 1;

Fig. 3 is a detail elevational view of the fllleting tool and its associated parts;

Fig. 4 is a detail inverted plan view of the iilleting tool shown in Fig. 3;

Fig. 5 isa detail end view of the filleting tool shown in Fig. 3;

Figs. 6, 7, 8 and 9 are sectional views through the blades of the filleting tool on the lines 6 6, 'l-l, 8-8 and 9-9 respectively of Fig. 3, looking from the left of Fig. 3 to the right thereof. In these figures a section through a fish and the prismatic portion of its backbone is shown in phantom. The fish is assumed to be far enough along the blades so that the positions indicated in said figures denote simultaneous cutting action. In addition in Fig. 6 a phantom cross-section of the oval portion of the spinal column of the fish is included merely for the purpose of illustrating in this same figure the initial relationship of the blades and this particular portion of the spinal column.

Fig. 10 is a, detail fragmentary elevational view of the filleting tool illustrating the start of the fllleting operation.

Fig. 11 is an elevational view of one side of the modified fllleting tool.

filleting tool taken on the line I2'-I2 of Fig. 11; a fish and the prismatic portion of its backbone being shown in phantom to illustrate how the blades cut the fish into two fillets.

As shown in Fig. l, the machine comprises a conveyer Il) adapted to convey by tail clamps I the decapitated ilsh II (tail foremost) with its ventral or underside directed towards a double bladed illleting tool I2 arranged to operate upon the ilsh after it has been previously slit along the two sides of the at or oval spinal column up to the navel or base of the prismatic portion or the spinal column by parallel` rotary disc knives I3 mechanically rotated by means not shown and hung from brackets I4' so that the knives can be lifted automatically by an arrangement such as shown in Figs. 1 and 2 when they reach the prismatic portion of the spinal column of the ilsh. This arrangement as illustrated may comprise a cam 45 rotated in timed relationship with the conveyer I0, a cam roller 46 riding on said cam 45 and actuating a lever 41 fixed to one end of a sleeve 58 rotatably mounted on a shaft 49 and an arm 5I ilxed to the opposite end of the sleeve 58 and carrying said slitting knives I3 on a shaft 52. It will be noted that with this arrangement the cam 45 periodically raises and lowers the knives I3 through the interposition of the parts described.

The illeting tool I2 is attached to a bridge member'll straddling the conveyer I8 and the iilleting tool I2 comprises a pair of blades indicated as a whole by the numeral I8 and spaced apart and having pointed forward extremities I9.

Each blade I8 has an elongated narrow forward portion 2l formed with an upper cutting edge 2Ia and a lower cutting edge 2lb which diverge gradually from lone' another -from the pointed extremity I9. The cutting edges 2Ia and 2lb are formed by grinding off the outer face of the blade. 'I'he blade I8 continues backwards from the cutting edge 2Ia in a gradual upward curve 23 which is formed as a cutting edge by grinding oir the inside face of the blade. The lower cutting edge 2lb is continued backwards as a blunt edge 24a which rises with a more gradual curve than the edge 23 and nally terminates in a straight blunt lower edge 24h. From the pointed extremity I9 to the rear of the cutting edge 23 the blade gradually increases in width, that is to say, in distance between its upper and lower edges. Also from about a point in rear of the line 'I-'I the blade is curved transversely, as more clearly seen in Figs. 8 and. 9 until it iinally terminates at the rear in the wider rear portion 22. The edge 23 thus curves both upwards and outwards from front to rear and the edge 23 and transverse curvature of the blade are made to conform to the curved shape of the sides of the prismatic portion lof the spinal column of the fish on which the iilleting tool is designed to operate. Thus the edge 23 and transverse curvature of the blade will be determined by the anatomy and size of the ilsh to be lleted by the tool.

Each blade I8 (see Fig. 5) has an integral lug portion 25 to the inside face of which is secured a block 26. The two blocks 25 tit side by side in a box-shaped holder I8 which is carriedy at the lower end of a square stud I6a. The stud I 5a is held between a pair of guides or clamps 39 secured to the underside' of a cross-bar 48 which fits under the bridge member I'I. A screwthreaded pin 25a projects up from the square Fig. l2 is a cross-sectional view of the modliied.

. i stud I5a (Figs. 3 and 5) bridge member I'I (Figs.l 1 and 2) to receive a nut 21 or the like for suspending the blades I8 from the bridge member I1. 'Ihe distance between the blades I8 can be adjusted either by substituting wider blocks 26 or by inserting distance pieces between the blocks 26.

through the bar 45 and An arm 28 (Fig. 3). is pivotally attached at 28 to an extension 30 on the box-shaped holder I6,

said arm 28 being situated over the space between the two iilleting blades I8.

'I'he arm 28 is prevented from descending beyond a predetermined limit by an adjustable abutment screw 4I (Fig. 3) on the arm 28 engaging a stop 42 (Fig. 4) projecting inwards from the side vo1 the machine. An upward extension 28a of the arm 28 is attached to one end of a spring 36, the other end of which is attached to any convenient xed part I1 of the machine. A forward extension 3| on the arm 28 is of such reduced thickness as to iit betwee the two parallel'slltting knives I3.

On the arm 28 is attached a chain 35 which passes over a pulley 48 xed in a convenient position on the machine and is then secured to the arm 5I which carries the slitting knives I3. .The chain 35 is of such length as to cause the arm 28 to be raised when the slitting knives I3 are at their lowest position and vice versa, the arm 28 being caused to fall by the action of the spring 35, to the prescribed limit xed by the adjustable abutment screw 4I when the knives I3 rise out of the iish. The object of this movement is to overcome the tendency of the slitting knives I3 to lift the iish oi the conveyer when they are raised. Therefore when the knives I3 are cutting, the arm 28 and extension 3| are raised, and as the knives I3 are raised, the parts 28 and 3l correspondingly lower on to the fish.

A circular toothed disc 32 is mounted on a shaft 33 supported in a bracket 34 secured to the stud I8a, the disc 32 being driven by flexible shafting 38, at a peripheral speed substantially equal to or slightly faster than the surface speed of the conveyer I0.

The operation of the machine is as follows:-

The previously decapitated and eviscerated fish gripped by the tail clamps I5 and resting on the conveyer I0 is'carried past the two parallel slitting knives I3 which slit open the iish-alongthe two sides of the oval spinal column indicated by the numeral a in Fig. 10 up to the navel N at the base of the prismatic'spinal column 20. The knives I3 are then lifted out by the arm 5I as the cam 45 raises the cam roller 46 and lever 41 and the sh is carried on towards the iilleting tool. The points I9 of the blades of the lleting tool pass along each side of the oval bone in the cut made by the circular splitting knives I3 and as the fish progresses the points I9 of the blades enter the iiesh at the sides of the prismatic bone as seen in Fig. 6, so that the fish is firmly impaled on the elongated narrow forward portions 2I of the blades. The forward blade portions 2I enter the iie'sh in a direction which is substantially parallel to the line of the prismatic spinalcolumn 28. When the prismatic section of the bone' reaches the curved cutting edge 23, the latter commences to cut the esh from the sides of the prismatic bones close thereto as clearly seen from Figs. 7, 8 and 9 until the sides oi' the prismatic bone have been cut from the flesh. During this operation, the prismatic bones pass between the blades I8 and out through the space at the back of the blades.

In order to prevent the points I9 of the lleting tool from passing through the back or dorsum of the fish, a device is preferably provided for holding down the head end H of the prismatic bone during the operation of the lleting tool. said holding-down device as shown comprises the extension 3| situated between the slitting knives I3, said extension 3i engaging the top of the prismatic bone as the fllleting blades I8 pass through the sh and holding the head end H of the prismatic bone down while the curved cutting edges 23 of the blades sever the flesh from the bone. The filleting operation is also caused to conform to the natural longitudinal curvature of the prismatic spinal column 20, the extension 3| riding over the curvedprismatic bone and thus enabling the filleting blades I8 to follow the longitudinal curvature of the central bone. The arm 28 holds the ilsh in contact with the cutting edges 23 as the fish passes between the blades I8.

The circular toothed disc 32 rests upon the at uppermost face of the prismatic bones and is rotated at such a speed as to assist in feeding the prismatic bones through the space between the blades I8.

As shown in Figs. 39, the lower edge 2Gb of the blades I8 is blunt and slightly elevated so that it does not cut, through the back of the fish. After the sh has left the lleting tool, the backbone may be completely cut out in known manner by angularly related rotary boning knives 31 so that the fish is produced as one fillet.

In the construction shown in Figs. 11 and 12, the blades I8' have their lower edges 24h formed as deep cutting edges which are designed to cut through the back of the sh on each side of the dorsal fins, so that the sh is delivered from the fllleting tool in the form of two fillets.

The machine may be fitted with alternately operating slitting knives I3 arranged to slit the fish first along one side and then the other of the oval spinal column up to the prismatic bone, or the said slitting may be previously accomplished by hand labour.

Means are preferably provided for adjusting the illleting tool transversely with respect to the surface on which the fish rests and for adjusting the tool to vary the distance of the lleting blades from the conveyer or surface on which the fish rests and for adjusting the blades towards or away from each other.

If the conveyer track is straight as shown in Fig. 1, the blades of the lleting tool will be straight or substantially straight and parallel or nearly parallel to the straight conveyer track, as shown in Figs. 1-12, but if the ish are conveyed upon a curved conveyer track, the blades of the lleting tool will be curved to conform to the curvature of the conveyer track.

If desired, the two blades I8 of the lleting tool, as also the pair of circular slitting knives I3, may be arranged with the blades or knives in series one behind the other, so as to operate upon the fish in succession.

Instead of the conveyer shown, the fish may be conveyed while resting on its back upon or in the periphery of a rotary drum conveyer having a horizontal axis or while resting with its back upon or in the periphery of a rotary drum or rotary table type conveyer having a vertical or inclined axis, or the sh may rest with its back on or inthe surface of an endless belt or chain conveyer which may travel in a Vertical plane or in an inclined plane instead of in a horizontal plane as in Fig. 1. In all lcases the ventral portion of the fish to be presented to the .lieting tool will be directed outwards from the conveyer.

Alternatively the fish may rest. on its side in or on a conveyer of any of the above-mentioned types with the ventral portion of the fish presented to the nnen-ng tool, which in such-case will be situated laterally at one side of the conveyer and will be turned through degrees from the position shown in Fig. 1.

Although it is preferred to convey the tlsh as above indicated, the machine may be arranged to convey the fish with its ventral portion directed inwards or resting in or protruding through a slot in the conveyer surface, the filleting tool being encircled by the conveyer and operating upon the inwardly directed ventral portion of the fish.

We claim:

1. A lleting tool for a fish-dressing machine comprising a pair .of spaced'elongated blades positioned adjacent the surface of the machine upon which the sh rests, means for supporting said blades in position in relation to said surface, each of said blades having a pointed forward extremity and a cutting edge which gradually recedes further from said surface as the cutting edge approaches the rear of said blade, said cutting edges also diverging away from each other towards the rear of said blades.

2. A lleting tool according to claim 1 wherein the blades have parallel slightly curved underedges opposite said cutting edges, said underedges having their forward portions formed as cutting edges and their rearward portions made blunt and shaped to be positioned further from the surface upon which the fish rests than said under-edges are positioned at their forward portions.

3. A fllleting tool according to claim 1 wherein the blades have parallel and substantially straight under-edges opposite said curved cutting edges, said under edges being formed as cutting edges and approaching nearer to the surface upon which the fish rests as they approach the rear of the tool.

4. A filleting tool for association with the conveyer of a fish-dressing machine, comprising a pair of blades spaced uniformly apart at their lower edges and having their upper edges curved to recede from each other as they approach the rear and to curve upwards away from the lower edges as they approach the rear, said blades having sharpened forward portions and their upper edges formed as cutting edges.

5. A lleting tool as specified in claim 4 having means under which the prismatic portion of the backbone rides to hold it in contact with the curved cutting edges.

6. In a fish-dressing machine, a fish conveyor, means on the conveyor for engaging the tail of the sh after it has been decapitated and eviscerated, a pair of rotatably driven spaced parallel circular slitting knives associated with the conveyor and arranged to slit the fish on each side of the oval portion of the backbone, means for moving said knives into an inoperative position on reaching the prismatic portion of the backbone, a flleting tool in rear of the slitting knives, means for mounting said tool to operate upon the sides of the prismatic portion of the backbone, said tool comprising a pair of spaced elongated blades between which said prismatic portion passes, each blade having a curved cutting edge for cutting the flesh of the fish from the prismatic portion oi the backbone, and 'means associated with said lleting tool for resting on the prismatic bones to hold down the front portion thereof, thereby to prevent the pointed extremities of the blades from passing through the back of theflsh. I

7. In a fish-dressing machine, a fish conveyor, means on the conveyor for engaging the tail of the fish after it has been decapitated and eviscerated, a pair of knives associated with the conveyor andarranged to slit the fish on each side of the oval portion of the backbone, means ,for moving said knives into an inoperative position on reaching the prismatic portion of the backbone, a iilleting tool in rear of the slitting knives, means for mounting said tool to operate upon the sides of the prismatic portion of the backbone, said tool comprising a pair of spaced elongated blades between which said prismatic portion passes, each blade having a curved cutting edge conforming to the curved lateral shape of the prismatic portion of the backbone, and means associated with said filleting tool for causing the blades thereof to conform in operation to the longitudinal curvature of the prismatic portion of the backbone of the fish.

8.V In a fish-dressing machine', a fish conveyor, means on the conveyor for engaging the tail of the sh after it has been decapitated and eviscerated, a pair of knives associated with the conveyor and arranged to slit the fish on each side of the oval portion of the backbone, means for moving said knives into an inoperative position on reach,- ing the prismatic portion of the backbone, a ille leting tool in rear of the slitting knives, means for mounting said tool to operate upon the sides of the prismatic portion of the backbone, said tool comprising a pair of spaced elongated blades between which said prismatic portion passes, each blade having a curved cutting edge for cutting the iiesh of the fish from the prismatic portion of the backbone, a device situated between the slitting knives and adapted to rest on the fish, and a 'conveying element situated between the blades of said fllleting tool and engageable with the backbone of the fish to convey it through the space between the blades.

9. In a fish-dressing machine, a fish conveyor, 4means on the conveyor for engaging the tail of the sh after it has been decapitated and eviscerated, a pair of rotatably driven spaced parallel circular slitting knives associated with the conveyor and arranged to slit the fish on each side of the oval portion of the backbone, means for moving said knives into an inoperative position on reaching the prismatic portion of the backbone, a filleting tool in rear of the slitting knives. means for mounting said tool to operate upon the sides of the prismatic -portion of the backbone, said tool comprising a pair of spaced elon-l gated blades between which saidprismatic portion passes, each blade having a curved cutting edge for the fllleting operation, a device situated between the slitting knives and adapted `to rest on the fish, a toothed feed wheel rotatable between the blades of said lleting tool and engageable with the backbone of the fish, and means for rotating said Wheel.

10. In a fish-dressing machine, a fish conveyor, means for holding the fish on the conprismatic portion of the backbone, means for maintaining the sh on the conveyor as the slittingmeans are moved out of operative position and for\ olding the iish on the conveyor at a point spac d from said mentioned holding means, means for nlleting the fish closely along the natural curvature in the lengthwise direction of the backbone. and means contacting said backbone for conveying it through said filleting means.

, 11. In ay fish-dressing machine, a fish conveyor, means for holding the fish on the conveyor after it has been decapitated and eviscerated, means for slitting the sh on each side Vof the oval rtion of the backbone, means for automatic moving said slitting means out of operative\ position when said means reach the prismatic portion of the backbone, means for maintainixm/the fish on the conveyor as the slitting means are moved out of operative position and for holding the fish on the conveyor at a point spaced from said mentioned holding means, means for illeting the'fish closely along the natural curvature in the lengthwise direction of the backbone, means contacting said backbone for conveying it through said lleting means, andmeans for under-cutting said backbone to completely separate it from'the sh.

12. A filleting tool for mechanically removing the flesh from the prismatic portion of the backbone of a decapitated and eviscerated fish of the class described, comprisingr a pair of blades spaced apart for the passage of the backbone between them, and means for mounting said blades to operate upon the sides of the prismatic portion of the backbone, each blade having a pointed forward extremity, an elongated narrow portion in the rear thereof, and a portion which gradually increases in width towards its rear and has a curved cutting edge which conforms to the curved shape of the sides of the prismatic bone so as to cut close to the sides of said bone.

13. A lleting tool for mechanically removing the iiesh from the prismatic portion of the backbone of a decapitated and eviscerated fish of the class described, comprisingv a pair of blades spaced apart for the passage of the backbone between them, and means for mounting said blades to operate upon the sides of the prismatic portion of the, backbone, each blade having a pointed forward extremity, an elongated portion in the rear thereof, and a portion gradually increasing in width from said elongated portion toward its rear and having a cutting edge curved to cut close to the sides of the prismatic portion of the backbone, each blade being curved transversely from a point in the rear of its pointed extremity to the rear of said blade to conform to the transverse curvature of the sides of said prismatic portion.

14. A lleting tool for mechanically removing the flesh from the prismatic portion of the backbone of a decapitated and eviscerated sh of the class described, comprising a pair of blades spaced apart for the passage of the backbone between them, and means for mounting said blades to operate upon the sides of the prismatic portion of the backbone, eachblade having a pointed forward extremity, an elongated narrow portion in the rear thereof, and a portion which gradually increases in width towards its rear and has a curved cutting edge which conforms to the curved shape of the sides of the prismatic bone so as to cut close to the sides of said bone, a second cutting edge being provided on each blade at the edge opposite said curved cutting edge and being shaped to cut through the back of the iish to cause the iilleting tool to divide the fish into two iillets, one on each side of the backbone.

15. A lleting tool for mechanically removing the flesh from the prismatic portion of the backbone of a decapitated and eviscerated fish of the class described, comprising a pair of blades spaced apart for the passage of the backbone between them, and means for mounting said blades to operate upon the sides of the prismatic portion of the backbone, each blade having a pointed forward extremity, an elongated narrow portion in the rear thereof, and a portion which gradually increases in width toward its rear and has a curved cutting edge which conforms to the curved shape of the sides of the prismatic bone so as to cut close to the sides of said bone, a blunt edge being provided on each blade at the edge opposite said curved cutting edge and being shaped to avoid its penetration through the back of the iish.

16. A lleting tool for mechanically removing the esh from the prismatic portion of the backbone of a decapitated and eviscerated iish of the class described, comprising a pair of blades spaced apart for the passage of the backbone between them, and means for mounting said blades to operate upon the sides of the prismatic portion of the backbone, each blade having a pointed forward. extremity, an elongated-narrow portion in the rear thereof, and a portion which gradually increases in width towards its rear and has a curved cutting edge which conforms to the curved shape of the sides of the prismatic bone so` as to cut close to the sides of said bone, said filleting tool having associated therewith means adapted to rest upon said prismatic bone to hold down the front portion thereof and thereby prevent the pointed extremity of each blade from passing through the back of the sh.

17. A lleting tool for mechanically removing the esh from the prismatic portion of the backbone of a decapitated and eviscerated sh of the class described, comprising a pair of blades spaced apart for the passage of the backbone between them, and means for mounting said blades to operate upon the sides of the prismatic portion of the backbone, each blade having a pointed forward extremity, an elongated narrow portion in the rear thereof, and a portion which gradually increases in Width towards its rear and has a curved cutting edge which conforms to the curved shape. of the sides of the prismatic bone so as to cut close to the sides of said bone, said' filleting tool having associated therewithl means for causing the prismatic boneof the sh to contact with the lleting blades to enable said blades to follow the longitudinal curvature of said bone.

18. A lleting tool for mechanically removing the flesh from the prismatic portion of the backbone of a decapitated and eviscerated fish of the class described, comprising a pair of blades spaced apart for the passage of the backbone between them, a conveying element situated be- -tween the blades of the tool and engageable with the backbone of the sh' to convey it through the space between the blades, and means for mounting said blades to operate upon the sides of the of the prismatic bone so as to cut closeto the sides of said bone.

19. A iilleting tool for mechanically removing the esh from the prismatic portion of the backbone of a decapitated and eviscerated iish of the class described, comprising a pair of blades spaced apart for the passage of the backbone between them, a toothed wheel rotatable between the blades of the tool and engageable with the backbone of the fish to convey it through the space between the blades, and means for mounting said blades to operate upon the sides of the prismatic portion of the backbone, each blade having a pointed forward extremity, an elongated narrow portion in-the rear thereof, and a portion which gradually increases in width towards its rear and has a curved cutting edge which conforms to the curved shape of the sides of the prismatic bone so as to cut close to the sides of said bone. t

20. In a sh-dressing machine, a fish conveyer, means on the conveyer for engaging the tail of the fish after it has been decapitated and eviscerated, a slitting device associated with the conveyer for slitting the fish from its tail, means for moving said slitting device into an inoperative position when it reaches the prismatic portion of thebackbone, a lleting tool immediately behind the slitting device, and means for rigidly mounting said tool relatively to the conveyer, said tool comprising a pair of spaced elongated blades terminating in pointed forward extremities and increasing gradually in width towards the rear, each blade having a curved cutting edge which conforms to the curved shape of the sides of the prismatic portion of the backbones of the fish which pass between said blades.

21. In a fish-dressingmachine, a fish/conveyer, means on the convey/er for engaging the tail of the sh after it has been decapitated and eviscerated, a pair of rotatably driven spaced parallel circular slitting knives associated with the conveyer and arranged to slit the sh on each side of the oval portion of the backbone, means for moving said knives into an inoperative position on reaching the prismatic portion of the backbone, a iilleting tool in the rear of the slitting knives, means for mounting said tool to operate upon the sides of the prismatic portion of the backbone, said tool comprising a pair of spaced elongated blades between which said prismatic portion passes and each blade having a cutting edge curved to cut close to the side of the pris-i matic portion of the backbone, and a device situated between the slitting knives and adapted to rest on the fish.

22. In a sh-dressing machine, a iish conveyer, means on the conveyer for engaging the tail of the iish after it has been decapitated and eviscerated, a pair of rotatably driven spaced parallel circular slitting knives associated with the conveyer and arranged to slit the sh on each side of the oval portion of the backbone, means for moving said knives into an inoperative position on reaching the prismatic portion of the backbone, a iilleting tool in the rear of the slitting knives, means for mounting said tool to operate upon the sides of the prismatic portion of the backbone, said tool comprising a pair of spaced elongated blades between which said prismatic portion passes and each blade having a cutting edge curved to cut close to the side of the prismatic portion of the backbone, a device situated between the slitting knives and adapted to rest on the fish, and a pair of angula'rlyrelated -rotatable knives in the rear oi' the iilleting tool for under-cutting the backbone of the fish. to completely separate it therefrom.

y 23.. A lleting tool for a nah-dressing machine comprising a pair of spaced elongated blades, an adjustable means for mounting said blades in proper relationship to the machine, each blade comprising an elongated narrow forward portion. an upper cutting edge formed on said por- 10 tion, a lower cutting edge formed on said portion, said edges'gradually diverging from one another from a pointed extremity on said portion, a gradually rising `'upwardly curved edge extending back from saidupper cutting edge and formed 15 as a cutting edge, a lower upwardly ,curved blunt edge extending back from said lower cutting edge and lrising with amore graduabcurve than said upwardly curved edge anditerminating in a lstraight edge, and each blade'having a trans- I verse curvature, and the upwardly curved cutting edge and the transverse curvature oi.' each biade being determined by the anatomy. and size of the tion, a gradually rising upwardly curved edge Y extending back iromsaid,. upper cuttingv edge and formed as a cutting* edge, a lower upwardly curved blunt edgev extending back from said `lower cutting edge and rising with a more gradual curve than-said upwardly curved edge and terminating in a straight edge, and each blade 40 having a transverse curvature,` the upwardly curved cutting edge curving outwardly from front kto rear and said cutting edge and the transverse curvature oi each blade being made to confrom to the curved shape of the sides of the prismatic portion o! the spinal column oi the particular class of sh on which said tool is to operate.

25. A iilleting tool for a fish-dressing machine, comprising a pair of spaced elongated blades,

S an adjustable means for mounting said blades in proper relationship to the machine, each blade comprising an elongated narrow forward portion, an upper cutting edge formed on said portion, a lower cutting edge formed on said portion, said edges gradually diverging from one another from a extremity on said portion, a gradually rising upwardly curved edge extending back from said upper cutting edge formed as a cutting edge, a lower deep cutting edge extending back from said-lower cutting edge and curving downwardly toward" the fish, and each blade having a transverse curvature, the upwardly curved cutting edge and the transverse curvature of each blade being determined a5 by the anatomy and sise o! the sh to be iilleted. "26. A illletingl tool for a shg machine, comprising a pair of spaced elongated blades, an adjustable means ior mounting said blades in proper relationship to the machine, said blade comprising an elongated narrow forward portion. a gradually rising upwardly curved edge,

extending 'back from said upper cutting edge l and `formed as a cutting edge, a lowerdeep cutl ting edge extending back from said lower cutting edge and curved 4downwardly toward the fish, and each blade havingv a transverse curva- 5 ture, the upwardly curved cutting edge curving outwardly -from iront to rear and said cutting edge and the transverse curvature of each blade beingmade to conform to the curved shape o! the sides oi' the prismatic portion of the spinal 1o column of the particular class ot ilsh on which said tool is to operate.

27. In a tlshfdressing machine, a nsh conveyer, means on the conveyer tor engaging the tail oil the fish after it has been decapltated and la tion of the backbone, said tool comprising a pair 2o of spaced elongatedblades between which said prismatic portion passes and a cuttingv edge 0n each blade curved to cut close to the side of the prismatic portionoi said bone, the front portions oi said blades lying in parallel planes and having 30 slightlycurved under-edges opposite said curved cutting edges, said under-edges having their forward portions formed as cutting edges and their rearward portions. made blunt and shaped to be positioned further from the surface upon 35 which the fish rests than said undereedges-are positoned at their forward portions, and a device situated between the slitting knives and adapted to rest on the fish.

28. In a fish-dressing machine, a fish con- 40 veyer, means on the conveyer for engging the tail oi the iish alter it has been decapltatad and. eviscerated, a pair of rotatably driven spaced parallel circular slitting knives associated with the conveyer and arranged to slit the iish on 45 each side of the oval portion of the backbone. means for moving said knives into an inoperative position on reaching the prlsmatic portion oi the backbone, a lleting tool in the rear. of the slitting lmives, means for mounting said tool to 50 operate upon the sides of the prismatic portion of the backbone, said tool comprising a pair v0I spaced elongated blades between which said prismatic lportion passes.. d a cutting edge on each blade curved to cu close to the side. ot the 55.

prismatic portion oi.' the backbone, the iront portions of said blades lying in parallel planes and having under-edges opposite said curved cutting edges, said under-edges being formed as cutting edges and approaching nearer to the surface a0 upon winch the nsh rests as it approaches the rear of the tool, and a device situated between the slitting knives and adapted to reist on the fish.

29. In a sh-dressing machine, ansh con- 05 veyer, means on the conveyer for engaging the v tail of the iish after it has been decapitated and eviscerated, a pair oi' rotatably driven spaced parallel circular slitting knives associated with the conveyer and arranged to slit the ilsh on 70v each side of the oval portion of the backbone,

vmeans for moving said knives into `an inoperative vposition on reaching the prismatic portion of the backbone, a lleting tool in the rear oi the slitting knives, means for mounting said tool 15 to operate on the sides of the prismatic portion of the backbone, said tool comprising a pair of spaced elongated blades between which said prismatic portion passes, each blade having a cutting edge curved to conform to the curved shape of the side of said prismatic portion and thereby cut close thereto, a second cutting edge being provided on each blade and being shaped to cut through the back of the fish to cause the tool to divide the sh into two fillets, one on each side of the backbone, and a device situated between the slitting knives and adapted to rest on the sh.

30. In a, sh-dressing machine, a sh conveyer, means for holding the sh on the conveyer after it has been decapitated and eviscerated, means for slitting the sh on each side of the oval portion of the backbone, and means for fllleting the fish, comprising blades having cutting edges curved to make a cut that conforms to the curved shape of the sides of the prismatic portion of the backbone.

31. In a sh-dressing machine, a sh oonveyer, means for holding the sh on the conveyer after it has been decapitated and eviscerated, means for slitting the fish on each side of the oval portion of the backbone, and means for fllleting the fish, comprising blades having front portions lying in substantially parallel planes and rear portions curved transversely to conform to the curved lateral shape of the prismatic portion of the backbone.

HAROLD STANLEY ROWTON. JOHN LESLIE ROWTON. 

